Electronic logic circuitry control for staple fiber baling device



Nov 22 1966 J. H. MARTIN, JR 3 286 21 ELECIHggIC LOGIC CIRCUITRY CONTROL FOR ,6 APLE FIBER BALING DEVIG Flled June 11, 1964 E 2 Sheets-Sheet 1 FIG- ALARM CIRCUIT RAM DRIVE CONTROLLER AMPLIFIER RELAY RANDOM PATTERN MISSED- SIGNAL DETECTOR POWER SUPPLY SENSOR ll U ATTORNEY Nov. 22, 1966 J. H. MARTIN, JR 3,286,621

ELECTRONIC LOGIC CIRCUITRY CONTROL FOR STAPLE FIBER BALING DEVICE Filed un 11, 1964 2 Sheets-Sheet 2 C9 .1 o a: 6

I LD C'; TQ ma I: I g L E (:0 \/\/l l 2 a a: a? g g a k g 8 INVENTOR JAMES HENRY MARTIN, JR.

ATTORNEY United States Patent 3,286,621 ELECTRONIC LOGIC CIRCUITRY CONTROL FOR STAPLE FIBER BALING DEVICE James Henry Martin, Jr., Waynesboro, Va., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed June '11, 1964, Ser. No. 374,304 Claims. (Cl. 100-45) This invention relates to the automatic regulation of the size of a staple fiber bale in the process of compressing the fibers into the bale by means of a power operated ram. Electronic logic circuitry included in this invention has potentially broad .fields of application.

The embodiment of this into a staple baler regulator is' a preferred embodiment of this invention.

In the past the size of a staple bale has been regulated by weighing the fiber prior to compressing it into -a bale or by manually interrupting the process when it has been determined visually that the required bale size has been reached. The first type of regulation is often not satisfactory because a bale of pre-selected density instead of weight is desired and because weight monitoring is complex, generally impractical, and, for some types of fiber bales, generally impossible. In some devices, for example the type disclosed in US. Patents 2,682,137 and 2,682,139 ram operation is discontinued as a result of the closing of a pressure switch located within the hydraulic actuator for the ram.

It is an object of this invention to provide automatic detection of the event that a bale of staple fiber has reached a pre-selected volume under pressure of a ram and then to shut down the bale filling and compressing operation and to accomplish these operations by means quired of fiber in the bale.

These objects are achieved by the apparatus of this invention which comprises, in a staple fiber baling device in which fiber is progressively dropped into a container and then compacted by a power-operated ram:

upper and lower electrical switches located at adjustable positions adjacent the path of a moving part of the ram; means fixed to said moving part which acts to temporarily close either switch when and only when such means is'approaching and in near proximity to the switch while moving in a proper logical direction, the

upper switch effectively located at the position reached by said means when the ram is retracted from the container, the lower switch effectively located just below the position reached by said means when the ram is compressing a .full bale; an electric power source connected to the switches so that when they are closed they fur- .nish pulse signals to electronic logic circuitry, comprising a flip-flop circuit combined with an AND gate, ar-

ranged to accept pulses from the two switches and give an output only if the upper switch furnishes two consecutive pulses without an intervening .pulse from the lower switch circuit but which will not give an output upon receipt of tconsecutivepulses fromthe lower switch circuit; and an amplifier or other means which accepts the output .from the logic circuit and operates a power relay to stop the ram motion and actuate .an alarm.

.By the expression effectively located is meant to indicate a location in which it operates; for magnetic switches tion.

"ice

this in the position at which the magnetic field becomes sufliciently strong to operate the switch.

A preferred embodiment of this invention is disclosed in the description given below in which reference is made to the attached drawings wherein:

FIGURE 1 is a schematic elevational view, partially in section, of a baler of this invention;

FIGURE 2 is a schematic block diagram showing the electronic components of this invention;

FIGURE 3 is a circuit diagram showing .one embodiment of .the electronic components of this invention; and

FIGURE 4 is an isometric view of an upper sensor with an arrangement to extend the distance over which the single upper sensor is actuated only one time during the rise and descent portions of the closing means which are above the effective position of the sensor.

A typical staple fiber baler, to which this invention can be applied, is shown in FIGURE 1 and comprises a bin 10 in which a bale is formed of staple fiber 12 supplied from chute 14 when a fence 16 is raised in a vertical direction by a ram 18 during its upward motion. Ram 18 is moved up and .down under actionof hydraulic power cylinder 20 to which it is attached .by a shaft 19, received by the cylinder 20, and is guided in this motion by guide shafts 22 which run in fixed tracks or channels (not shown). Ram position sensors comprising, in the preferred embodiment, magnetic reed switches 24, 26 and 28 are located near the path of a magnet 30 fixed to one of the .guide shafts 22. The effective positions of switches 24, 26, 28 are adjustable along this path. A scale 32 may be provided adjacent the housing for switch 28 to be used in setting the position of this switch relative to predetermined full-bale height.

Electric cables 34, 36 and 38 extend from switches 24, 26 and 28 to the electronic devices described .below.

Switches 24, 26 and 28 in this embodiment are magnetic reed switches .of conventional design whose contacts are closed without bounce when magnet 30 is brought near them by motion of the ram guide 22 to which the magnet is attached. The contacts of a given switch snap open as soon as the magnet leaves the vicinity of that switch.

The block diagram of FIGURE 2 shows the electrical connections and electronic components of the invention. A first sensor U and a second sensor B, each receive DC. power from power supply 40 over lines 41, 42 and 44. Sensor U corresponds to switch 26 while sensor B corresponds to switch 28 with switch '24 :in parallel. .Each sensor when actuated furnishes a pulse signal lines 46 or 48 to a novel type of random-pattern missed-signal detector 50. DC. power from supply 40 .1s furnished to detector 50 over line 52. Detector 50,

when it receives a logically determined pulse sequence, furnishes an output over line 54 to amplifier/relay 56 which also receives DC. power from power supply 40 over line 58. Amplifier/relay 56 is further connected over lines 60 and 62 to an alarm .circuit 64 and a ram drive controller -66.

In FIGURE 3 there is shown a preferred embodiment of the electronic logic circuitry and associated elements of the control device and their manner of interconnec- Magnetic reed switches 24 and 28 are connected in parallel. The input side :of each isconnected to one positive terminal 41, of DC. power supply-40. One side of magnetic reed switch 26 also is connected-to positive terminal 41 of supply 40.

Random-pattern, missed-signal detector 50 .is shown to comprise, first, a flip-flop circuit containing transistors Q and Q arranged to operate under certain pre-selected conditions, and, second, an electronic AND .gate comprising transistors Q and Q The emitters of transistors Q and Q are connected together and thence through resistor R to ground. The collector of transistor Q is connected through resistor R to the base of transistor of Q Likewise the collector of transistor Q is connected through resistor R to the base of transistor Q The collector of transistor Q is also connected through resistor R to positive terminal 41 of D.C. power supply 40. Likewise, the collector of transistor of Q is connected through resistor R to the same terminal 41 of the D.C. power supply.

The output terminal of the switch 26 is connected through a parallel circuit comprising capacitor C and resistor R to the base of transistor Q This same terminal of switch 26 is further connected to one side of a parallel circuit comprising, in one leg, resistor R and in the other leg capacitor C in series with resistor R the other side of this parallel circuit is grounded. From a point between capacitor C and resistor R a line is connected through resistor R to the base of transistor Q The output terminals of switches 24 and 28 are connected to the collector of transistor Q The collector of transistor Q is further connected through capacitor C and resistor R to the base of transistor Q From a point between capacitor C and resistor R lines connect to resistor R thence to the emitter of transistor Q, as well as to ground. The emitter of transistor Q is connected directly to the collector of transistor Q The collector of transistor Q is connected through resistor R to positive terminal 41 of D.C. power supply 40. The collector of transistor Q; is also connected through capacitor C to the base of transistor Q This base terminal of transistor Q is further connected through resistor R to a second positive terminal 58 of D.C. power supply 40. The emitter terminal of transistor Q is connected through resistor R to this same second positive terminal 58 of power supply 40 and through a normally closed disconnect switch S to one side of a relay coil CR-l. The other side of the coil CR-l is connected to the anode of a controlled rectifier (SCR-1), the cathode of which is connected through resistor R to ground. The collector of transistor Q is connected to the gate terminal of the rectifier SCR1 and to one side of a parallel circuit comprising, in one leg, a resistor R and in the other leg a capacitor C with the other side of this parallel circuit being connected to ground. Relay coil CR-l, which is bridged by capacitor C operates normally open contact S and normally closed contact S Contact S is connected to alarm circuit 64. Contact 5., is connected to the ram drive control circuit 66.

In FIGURE 3, sensor U is shown being composed of a single magnetically operated reed switch 26. Sensor B, on the other hand, is shown to be composed of two identical magnetically operated reed switches 24 and 28 located on opposite sides of sensor U adjacent the path of ram guide 22. These two latter switches are designated as a single sensor B in FIGURE 2 since they are connected in parallel and actuation of either switch will cause an identical pulse to be introduced at the same point in detector 50.

As will be seen from the operation of detector 50 described below, the upper or second switch 24 of sensor B is arranged to provide for an overrun of the ram guide 22 in the upper direction past switch 26 of sensor U and thus provide a signal pulse from sensor B prior to the subsequent down stroke of the ram and a second operation of switch 26 in sensor U. In the event that the apparatus to which the circuit is applied is so constructed that no overrun will be experienced and switch 26 can be located at the peak of the upward stroke, the extra switch 24 of sensor B can be eliminated. An alternate means for eliminating the extra switch 24 in sensor B is shown in FIGURE 4. In this case, two long bars 68, 68 of soft magnetic material, extending from the effective position of switch 26 when magnet 30 is rising to above the uppermost position of magnet 30, are fixed to the housing 4, of switch 26 and extend parallel to the direction of motion of magnet 30. These bars provide an extended magnetic circuit which includes switch 26 so that this switch will be closed and opened only one time when magnet 30 moves into and out of the normally effective region for actuating this switch. This arrangement is shown in dotted lines on FIGURE 1. Of course when it is used, switch 24 and line 42 are omitted.

In operation the random-pattern, missed-signal detector 50 is an electronic logic circuit operating to provide a signal when a pre-selected event did not happen. In this particular application to a fiber baler, this specific event is the condition that the ram, in a downward stroke, does not reach a pre-determined lower level as sensed by sensor B, thus indicating that the fiber bale is full. On a subsequent up stroke the detector 50 remembers that the ram did not descend to or below the full-bale position and, upon a signal from sensor U, the detector furnishes a signal which energizes the amplifier/relay 56 and thus sounds an alarm and stops the ram motion. Basically then, detector circuit 50 accepts positive pulses from two sensors (sensor Uthe upper, sensor B-the bottom) and gives an energizing signal to the amplifier/relay 56 if and only if the upper sensor U furnishes two consecutive signals without an intervening signal from the bottom sensor circuit. Furthermore, detector circuit 50 is so constructed that any number of consecutive pulses from the bottom sensor circuit will not cause an output from detector 50.

As evident from FIG. 3, the random-pattern, missedsignal detector 50 comprises first a common emitter flipflop containing transistors Q and Q coupled with an electronic AND gate containing transistors Q and Q During a normal cycle of motion of the ram 18 (that is, when the fiber bale is not full) magnet 30 will pass and operate each of the three switches 24, 26 and 28. The common emitter flip-flop comprising transistors Q and Q are resistive coupled between the collector and base of both transistors. In the initial state, Q is. turned on and Q is turned off. When the magnet 30 passes switch 26 (sensor U) thereby closing it, a large positive pulse (e.g. 15.5 volt) is applied to line 46. An A.C. (capacitive) coupled positive pulse through capacitor C causes a positive pulse spike into the base of transistor Q with a duration determined by its RC feed (C R which is less than the duration of that on line 46. Thus the signal to the base of Q; is an electronically diiferentiated signal relative to the signal on line 46. At the same time, the large positive pulse of line 46 is applied to the base of transistor Q through the parallel RC circuit composed of R and C This base voltage is also a differentiated signal relative to the line 46 signal. However, current through R by-passes capacitor C to maintain a current to the base of transistor Q as long as current remains at its peak positive level on line 46 (i.e. as long as switch 26 remains closed). Since Q is on, Q is oil and base current for Q is also received through R from line 41. Capacitor C charges to the difference in voltage bet-ween line 46 and the voltage at the base of Q That transistor stays on. R, develops an almost instantaneous drop from the high positive voltage on line 46 to ground. Transistor Q which is off, remains oif and its collector remains near the high positive voltage of line 46.

The end of the positive pulse applied through the switch 26 to line 46 occurs when that switch opens, as when magnet 30 moves out of its area towards switch 28. Thereupon C discharges through R and R thus holding line 46 positive for the time constant interval approximately equal to (R +R9) C Starting simultaneously with the opening of the switch 26, C discharges mainly through R with a time constant longer than the C dis-charge time. Thus, the negative pulse spike from C across R7 to ground is applied to the base of transistor Q through C because the C voltage drop is maintained for a longer time.

occurs wherein that switch fails to close.

This negative pulse to the Q base, which is a negative differentiated signal at the end of the positive pulse on line 46, causes transistor Q to cut off and the direct coupling to transistor Q (Q collector to Q base) causes Q to turn on.

Continuing the normal sequence, when magnet 30 gets to the effective location of bottom switch 28 (sensor B), that switch closes to place a positive pulse on line 48. This pulse reaches the base of Q through the RC series of C and R The direct positive pulse also reaches on by the continuing positive signal from the B-[ positive supply, through line 41, R and R (Q collector remains positive) into the Q base.

As magnet 30 causes closure of switch 26 again the cycle previously described is repeated. This alternate switching upon sequential opening and closing of the two switches causes an alternating positive pulse to either the Q or Q, base as described, but at no time do both Q and Q receive simultaneous positive pulses. Thus with the cycle described so far, the current through R never changes and no voltage pulse can be received by C Current will flow through R only when both Q and Q conduct at the same instant. This condition does not occur inthe above described normal sequence wherein the baler ram stroke reaches a point below the effective location of switch 28 thereby closing it and indicating a non-full bale.

- When the bale is filled to the preselected "level, the ram will no longer descend to the effective position of the switch 28-and a therefore downward ram stroke This causes the circuit of switch 26 to close a second time without an intervening closure of the switch 28. At this time (sequence-switch 26 on, then off, and no response from switch 28) transistor Q is off and Q on because the last state change occurred when switch26 opened, as was noted above.

Under these conditions, that is, closure of the switch 26 with Q off and Q on after missed operation of switch 28 because of a full bale situation, a positive pulse is applied to line 46. As before, an A.C. (capacitive) coupled positive pulse into the base of Q occurs. Simultaneously, the positive pulse is applied through R and C to the base of Q which is now in the off state and therefore must turn on. The simultaneous turn-on of Q causes its collector simultaneously to go negative and turn oil Q while the collector of Q goes positive. The positive square wave from the Q collector gives a positive pulse to the base of transistor Q And as before, an A.C. (capacitive) couple-d positive pulse through capacitor C causes a positive pulse spike into the base of transistor Q Since Q and Q both received a positive signal at the same time, they conduct and a negative spike develops across R which is A.C. (capacitive) coupled to the base of transistor Q The negative spike through C causes Q; to conduct, Which generates a positive pulse in R and a negative feedback pulse on R The positive pulse on R charges capacitor C and injects a firing current into the gate of SCR-l which energizes relay CR-l, and the rectifier SCR-1 remains fired, because the load exceeds its holding current, until reset. Operation of relay coil CR-l serves to open contacts S which open the circuit to the ram drive controller 66 thereby promptly stopping the ram before it has reached a height sulficient to open fence 16. Coil CR-l also closes S thereby sounding alarm 64 indicating a full bale.

In the detailed operation just described the embodiment in Which a magnetic yoke is employed was demonstrated. The yoke is exemplified in FIGURE 1 by the dotted lines and shown isometrically in FIGURE 4, and is used in conjunction with switch 26 to-extend its effective range and switch 24 is omitted. As noted earlier the third switch (24) can be used, in which case the yoke, i.e. bars 68 and 68', are omitted. From the description given with respect to two switch operation, it is evident that the presence of switch 24 merely acts as a repeated operation of switch 28, returning the flip-flop .to a state such that a pulse through switch 26 will not cause both gates to receive a pulse, and therefore detailed description of its operation is unnecessary.

It will be appreciated that the described invention can be .practiced with the use of various electrical components. One listing of suitable commercial equipment is as follows: For switches 24, 26 and 28, Hamlin Type MRG-l is suitable; R is 220 ohms; R R and R are 56 kiloohms; R and R may be 3.3 kilo-ohms; R and R are 18 kilo-ohms; R and R are 10 kilo-ohms; R and R are 4.7 kilo-ohms; R suitably .is 2.2 kilo-ohms; R and R are ohms; R is 22 ohms; C C C and C are 0.1 microfarad; C and C are 1.0 microfarad; a suitable silicon controlled rectifier, SCR-1 is available from Sar-ks Tarzian as type 3TCRA; commercially available transistors for Q and Q are type 2N1302; for transistors Q and Q type TI-486 is used and type 2N527 is .used for transistor Q A suitable DC. power supply '40 provides 15.5 volts on line 41 and 17.01 volts on line 58, when measured at no load. Of course any number of other devices with different electrical properties could be used as well, as long as the described operations are achieved.

From the foregoing discussion and description it is evident thatthe present inventionprovides' effective monitoring of a bale filling operation and stops that operation when the predetermined state is achieved. Automatic control and alarm furnished by this invention has-distinct advantages over operator visual and manual control "by virtue of increased efficiency and accuracy in controlling the bale size. Additional applications-of :the electronic logic circuitry of this invention such as in machine tool control, process control, computer components, and pulse telemetry circuitry could be made by one skilled in the art.

While the invention has been described with respect to a detailed embodiment, it should be appreciated that changes can be made without departing from its scope.

What is claimed is:

1. In a staple fiber baling device comprising a container, and a power-operated staple-compacting ram, the ram being reciprocally mounted with respect to the container thereby defining a path through which the ram moves; at least two spaced electrical switches along the path of the ram including a source of electrical power connected to said switches; means movable when the ram moves and operable to close temporarily each electrical switch when close thereto; the lower of said electrical switches located at a position just below that reached by said means when the ram is compressing a full bale whereby said lower of the electrical switches remains inoperative; the upper switch effectively located to be closed temporarily by said means upon retracting the ram from compressing fiber in said container; electronic logic the ram, and second circuit means that upon the lower switch closing and applying a power pulse thereto operates to return said first circuit means from its first conducting state to its first stable state.

2. A staple fiber baling combination in accordance with claim 1 including gate means controlling the feeding of staple fiber to said container, said gate means being opened upon retraction of the ram from the container upwardly beyond its bale-full position, said upper electrical switch being located with respect to said switch closing means to close before the ram opens the gate means during the ram retraction stroke.

3. In a staple fiber baling device comprising a container, and a power-operated staple-compacting ram, the ram being reciprocally mounted with respect to the container thereby defining a path through which the ram moves; at least two spaced magnetically operated electrical switches along the path of the ram; magnet means movable when the ram moves and operable to close temporarily each electrical switch when close thereto; the lower of said electrical switches located at a position just below that reached by said magnet when the ram is compressing a full bale whereby said lower of the electrical switches remains inoperative; the upper switch effectively located to be closed temporarily by said means upon retracting the ram from compressing fiber in said container; magnetic yoke means about said upper switch to extend the eifect of said magnet thereon to the fully retracted position of said ram; electronic logic circuitry operable upon closing said switches comprising first circuit means including means to stop the ram, the first circuit means having a first stable state and adopting a first conducting state upon the upper switch closing and applying a power pulse thereto and then said switch opening, and in said first conducting state said first circuit means upon receiving a second pulse by virtue of a second closing of said upper switch operating to stop the ram, and second circuit means that upon the lower switch closing and applying a power pulse thereto operates to return said first circuit means from its first conducting state to its first stable state.

4. A staple fiber baling combination in accordance with claim 3 including gate means controlling the feeding of staple fiber to said container, said gate means being opened upon retraction of the ram from the container upwardly beyond its bale-full position, the lower portion of the magnetic yoke being located with respect to the magnet means to close the upper switch before the ram opens the gate means during the ram retraction stroke.

5. In a staple fiber baling device comprising a container, and a power-operated staple-compacting ram, the ram being reciprocally mounted with respect to the container thereby defining a path through which the ram moves; at least two spaced magnetically operated electrical switches along the path of the ram; magnet means movable when the ram moves and operable to close temporarily each electrical switch when close thereto; the lower of said eletcrical switches located at a position just below that reached by said means when the ram is compressing a full bale whereby said lower of the electrical switches remains inoperative; the upper switch effectively located to be closed temporarily by said means upon retracting the ram from compressing fiber in said container; electronic logic circuitry operable upon closing said switches comprising a flip-flop circuit and an AND gate circuit combined therewith, means responsive to the gate to stop the ram; the flip-flop circuit having a first stable state and adopting a first conducting state upon the upper switch closing and applying a power pulse thereto and then said upper switch opening, and in said first conducting state said flip-flop circuit upon receiving a second pulse by virtue of a second closing of said upper switch operating to operate said gate circuit to stop the ram; and the lower switch including circuitry that upon closing thereof applies a power pulse to the flip-flop circuit to return that circuit from its first conducting state to its first stable state.

References Cited by the Examiner UNITED STATES PATENTS 1,210,324 12/1916 Iohansen -45 2,682,137 6/1954 Cox 5324 2,682,139 6/1954 Cox 53124 2,967,951 l/1961 Brown 30788.5 3,201,599 8/1965 Baker et a1 30788.5

FOREIGN PATENTS 916,311 1/1963 Great Britain.

LOUIS O. MAASSEL, Primary Examiner. 

1. IN A STAPLE FIBER BALING DEVICE COMPRISING A CONTAINER, AND A POWER-OPERATED STAPLE-COMPACTING RAM, THE RAM BEING RECIPROCALLY MOUNTED WITH RESPECT TO THE CONTAINER THEREBY DEFINIG A PATH THROUGH WHICH THE RAM MOVES; AT LEAST TWO SPACED ELECTRICAL SWITCHES ALONG THE PATH OF THE RAM INCLUDINNG A SOURCE OF ELECTRICAL POWER CONNECTED TO SAID SWITCHES; MEANS MOVABLE WHEN THE RAM MOVES AND OPERABLE TO CLOSE TEMPORARILY EACH ELECTRICAL SWITCH WHEN CLOSE THERETO; THE LOWER OF SAID ELECTRICAL SWITCHES LOCATED AT A POSITION JUST BELOW THAT REACHED BY SAID MEANS WHEN THE RAM IS COMPRESSING A FULL BALE WHEREBY SAID LOWER OF THE ELECTRICAL SWITCHES REMAINS INOPERATIVE; THE UPPER SWITCH EFFECTIVELY LOCATED TO BE CLOSED TEMPORARILY BY SAID MEANS UPON RETRACTING THE RAM FROM COMPRESSING FIBER IN SAID CONTAINER; ELECTRONIC LOGIC CIRCUITRY OPERABLE UPONN CLOSING SAID SWITCHES COMPRISING FIRST CIRCUIT MEANS INCLUDING MEANS TO STOP THE RAM, THE FIRST CIRCUIT MEANS HAVING A FIRST STABLE STATE AND ADOPTING A FIRST CONDUCTING STATE UPON THE UPPER SWITCH CLOSING AND APPLYING A POWER PULSE THERETO AND THE SAID UPPER SWITCH OPENING, AND IN SAID FIRST CONDUCTING STATE UPPER FIRST CIRCUIT MEANS UPON RECEIVING A SECOND PULSE BY VIRTUE OF A SECOND CLOSING OF SAID UPPER SWITCH OPERATING TO STOP THE RAM, AND SECOND CIRCUIT MEANS THAT UPON THE LOWER SWITCH CLOSINNG AND APPLYING A POWER PULSE THERETO OPERATES TO RETURN SAID FIRST CIRCUIT MEANS FROM ITS FIRST CONDUCTING STATE TO ITS FIRST STABLE STATE. 